On Monday, Fema announced more than 500 million US dollars (£378 million) in aid to Puerto Rico, including 285 million US dollars (£215 million) to help restore power and water services to the devastated island. An additional 16 billion US dollars (£12 billion) would permit the financially troubled federal flood insurance programme to pay an influx of Harvey-related claims.

But the bill rejects requests from the powerful Texas and Florida congressional delegations for additional money to rebuild after hurricanes Harvey and Irma.

Florida Democrat Bill Nelson, whose state's citrus industry endured significant losses during Irma, sought to add three billion US dollars (£2.2 billion) in immediate agriculture assistance to the measure, but was denied by Majority Leader Mitch McConnell, who said money for crop losses would be in subsequent aid measures.

Senate passage on Tuesday would send the measure to President Donald Trump for his signature.

There was urgency to move the measure swiftly - rather than add more money to it at this time - because the government's disaster response and flood insurance reserves are running out. Democrat Senator Patrick Leahy of Vermont said that would happen "in a matter of days" without action.

Still, members of the Texas and Florida delegations in Congress are unhappy because the measure failed to address extensive requests for additional hurricane rebuilding money. Texas, inundated by Harvey in August, requested 19 billion US dollars (£14 billion), while Florida sought 27 billion US dollars (£20 billion).

"I'm pretty disappointed with what the House sent over," Texas Senator John Cornyn said last week. But later, after speaking to both Mr Trump and White House budget director Mick Mulvaney, Mr Cornyn said he was promised that the White House would issue another disaster aid measure next month for Texas, Florida, and Puerto Rico. A fourth, and perhaps final, measure is likely to anchor a year-end spending bill.

"The victims of these hurricanes can continue to count on our support," said Mr McConnell said.

Up to five billion US dollars (£3.7 billion) of the measure's total could be used to assist Puerto Rico's central government and various municipalities that are suffering unsustainable cash shortfalls as Maria has choked off revenues and strained resources. An additional 150 million US dollars (£113.5 million) would help Puerto Rico with the 10% match required for Fema disaster relief.

More than one-fourth of the island's residents do not have potable running water and only 17% have electricity, according to Fema Just 392 miles of Puerto Rico's 5,073 miles of roads are open. Conditions in the US Virgin Islands are bad as well, with widespread power outages.

But Mr Trump last week graded his response to the Puerto Rico disaster a 10 on a scale of 10.

"President Trump seems more concerned about claiming credit for a job well done than the actual situation on the ground deserves, particularly in Puerto Rico," Mr Leahy said. "This is the hard part of governing," he added. "We dig in for the long haul, we stop patting ourselves on the back."